Matlab error how to fix?

hi everyone

i am intererested in creating a m by 2 matrix where the first column is a datetime and second column is numeric. I thought the below code would work but it is not. how can i fix my code?

Code:

Data = convertvars(Data, 2, @(x) datetime(x, 'InputFormat', 'yyyy-MM-dd'));
FilteredDataRealizedVol = Data(:,["TRADE_DATE","REALIZED_VOLATILITY"]);

MR_Volatility(:,1) = FilteredDataRealizedVol.TRADE_DATE;
MR_Volatility(:,2) = FilteredDataRealizedVol1 + S * (M - FilteredDataRealizedVol1);

Error:

Error using  () 
You cannot assign numeric values to a datetime array. Assign to the array's Year, Month, Day, Hour, Minute, or Second
properties, or use datetime(x,'ConvertFrom',...) to create datetime values for assignment.

Error in LinearRegression (line 51)
MR_Volatility(:,2) = FilteredDataRealizedVol1 + S * (M - FilteredDataRealizedVol1);

Thank you

Answer 1

[Walter Roberson]

You cannot fix your code. It is not possible to create a uniform array in which the first column is datetime and the second column is numeric.

You can create a table(), but not an array.

MR_Volatility(:,2) = FilteredDataRealizedVol1 + S * (M - FilteredDataRealizedVol1);

Note by the way that you are operating on the entire table FilteredDataRealizedVol1 there, not just on the realized volatility

[Manny]

thank you both. i created a table. the table is 1 by 2. i am getting an error when i try to assign values to the columns. i think i need to pad the newly created table with data so the sizes are the same. is this correct? if yes, how do i fix this?

Code:

FilteredDataRealizedVol1 = table2array(FilteredDataRealizedVol(:,"REALIZED_VOLATILITY"));

sz = [height(FilteredDataRealizedVol) 2];
varTypes = ["datetime", "double"];
varNames = ["TRADE_DATE","REALIZED_VOLATILITY"];
MRVolatility = table('Size',sz,'VariableTypes',varTypes,'VariableNames',varNames);

Error:

Error using  () 
Right hand side of an assignment into a table must be another table or a cell array.

Error in LinearRegression (line 55)
MRVolatility(:,1) = FilteredDataRealizedVol.TRADE_DATE;

[Walter Roberson]

MRVolatility{:,1} = FilteredDataRealizedVol.TRADE_DATE;

[Manny]

thank you so much!! it works now

Answer 2

[Voss]

"creating a m by 2 matrix where the first column is a datetime and second column is numeric"

You cannot mix data types in a matrix (or any array); all elements must be of the same class.

However, you might find that using a table works well.

https://www.mathworks.com/help/matlab/tables.html

https://www.mathworks.com/help/matlab/matlab_prog/create-a-table.html